Structure development in cyanate ester polymerization

We present results on the product distribution obtained from the polymerization of the dicyanate monomer of bisphenol A carried out under different reaction conditions. Small quantities of side‐products were observed using both size exclusion chromatography and high‐pressure liquid chromatography for samples polymerized under an inert atmosphere. Despite the presence of side‐products, the oligomer distribution from SEC, after correcting for differences in refractive index, was found to agree well with random branching predictions. Results from HPLC also confirm good agreement with the theoretical prediction. Furthermore, a gel conversion of approximately 0·51(‐0·01, +0·03) was measured for the inert atmosphere product, which is within experimental error of the ideal value of 0·50. The monomer content of a polymerization carried out open to the atmosphere, however, showed significant disagreement with theory. ©1997 SCI